How many miles?

[maximo]

Driving a new F250 2015 and have questions. How many miles will a tank of the fuel additive of DEF go? I know a warning will come on telling be when I need to add the DEF but am I better off just filling the tank every so often? Also when not pulling anything do you ever use the Tow/Haul mode for braking when travelling in steep mountains?

[hickory]

My 2011 will take about 1 gallon of DEF per 1000 miles when running empty. It will use more when towing. I just use the + - button on the shift lever for slowing for stop signs etc.

[steves]

I never checked the mileage but think it's around the 4,000 mark. What I do is periodically use the instrument display to see when it goes below 1/2 then I fill it.

[Simpson9508]

When the tank level is below 1/2 you should be able to add 2 1/2 gallons. I check it about very 2 weeks when I'm not on a trip. Check it every couple of days when traveling.

[BB_TX]

Same as above. 3-4,000 not towing and it will drop below 1/2. More frequently when towing.

I do sometimes use tow/haul not towing on steep declines to use exhaust braking rather than manually downshifting.

[1retired06]

I am not really sure. Varies with use, ie towing, town, etc. Bottom line for me, when the half empty mark comes up, I wait a couple of hundred miles and fill with the 2.5 jug from Walmart.

[WeBeFulltime]

I have heard many say that they add def at regular service time.

[Carl n Susan]

The design intent, according to my Ford source, was the DEF should last until the next oil change (around 7-8K miles). Personally, I check the level via the instrument panel display, and when it says under 1/2, I add a 2 1/2 gallon jug. It seems to be getting around 3-4K miles per addition depending on how much towing I have done.

I too use Tow/Haul or the +/- button on the gear shift when going up/down steep mountains even if I am not towing. It is easier than hitting the brakes all the time.

[Artemus Gordon]

I travelled average of 3500 - 4000 miles per box of DEF in tow mode. I just keep a box in the truck. Add when I think about it! It's $11.89 at Autozone.

[DonandBonnie]

Don't think you can give an absolute mileage for DEF. It depends on the load you are hauling and your driving habits. The tank on our F350 should hold 5 gallons, however we've found that to add that much the tank has to be empty. As others have said we watch the meter and add a 2-1/2 gal jug when the screen says under 1/2 full.

[hickory]

I forgot to mention, I saved a 2.5 gal container with the nice flex hose and refill it at a local truck plaza. It costs 2.74 per gallon compared to the 11.99(on sale)I paid for the original container of DEF.